Which number changes with the period, and which does not
Not every number on the screen obeys the same rule; once you know that, you can tell at a glance which one changes with what.
Total balance is not a period total but a wallet total: each wallet's own balance is added up, and what you have today is what comes out. Since dates are not part of it, it stays the same whichever period you pick; the wallet filter, on the other hand, changes it directly, and when you pick one wallet only that one goes into the sum. Income, expense and net are period totals: they count what happened in the range you picked. Net is what you get when you take expense away from income: the amount left in your pocket over that period.
The budget bars do not change with the range above; they always measure the current month. That is deliberate: a budget is a monthly limit, so even while you are looking at the last three months you need to see where you stand in this one. They do change with the wallet filter, though, just like the balance. The Upcoming payments (14 days) section is fixed too, always showing the next 14 days.
There is also a button that belongs to the table alone: Upcoming, the eye icon next to the Transactions heading. It shows or hides future dated payments and income in the table, but the cards and the charts are not affected. A transaction that disappears from the list has not been dropped from the totals.
The same four cards under two ranges: the balance in the dashed outline holds still while income, expense and net move